I haven't tried since I don't have anyone I need to use it with, but there's a way to set it to back up and sync using git (since they're all markdown files any

I haven't tried since I don't have anyone I need to use it with, but there's a way to set it to back up and sync using git (since they're all markdown files anyway). It wouldn't be real-time (you couldn't both have a document open at once), and you'd probably have to remember to push your changes. Syncthing might also work in a rather hacky way, but would probably also run into real-time collisions.